The present invention relates generally to power transfer systems, and in particular to a system and method for reducing electromagnetic interference (EMI) in alternating current (AC) power switching systems.
Three-phase power systems, such as those implemented on aircraft, often include three-phase loads connected in a wye configuration. Some aircraft manufacturers will not allow the grounding of the neutral point of these three-phase AC power loads. Because of this, the load often includes the neutral point of the wye circuit that is floating, instead of grounded. Floating neutrals are difficult to control, leading to increased chance for generated EMI during switching of the AC power to the load. To solve this problem in prior art systems, heavy inductors and large capacitors have been utilized to reduce the level of EMI. This adds unwanted weight and cost to the system. It is desirable to provide accurate zero-crossing power switching for ungrounded loads in three-phase systems in order to reduce the amount of generated EMI.